The materials used for illumination in former times were various kinds of animal fat. The first kerosene lamps were imported to Iceland in 1860. Half a century later the Reykjavík Gas Works started operating. This amounted to a revolution in Iceland‘s struggle against darkness and many people had gas lights installed in their homes. The Reykjavík Gas Works operated from 1910 to 1956 and produced gas for cooking and lighting from imported coal. When gas had been extracted from the coal by heating the coke residue was sold and used for burning and heating. After the Reykjavík Electric Company was established in 1921 gas was used almost exclusively for cooking.